Shuttlecocks

ABSTRACT

The invention relates to a shuttlecock having a cap and a flared skirt of a plastics material and formed of a plurality of main stems interconnected by a lattice work of further stems and transverse ribs in which slits are provided in the wide end of the skirt extending to its free edge, between the main stems, the slits being adjacent the main stems. The main stems adjacent the base of the skirt may be provided with strengthening flanges extending approximately one-third of the length of the main stems.

United States Patent Maconachie June 24, 1975 [541 SHUTTLECOCKS 2.734.746 2/1956 Sametz et a1. 273/106 A 2.761.685 9 1956 Lashle 273/106 A [751 111mm: Mamnacme, Sandwlch, 2,815,956 12/1957 1.2151116; 273/106 A England 3,100,116 8/1963 Fagan ct a1. 273 106 A Assigneez Reinforced Shutlecocks Carlton A London, England FOREIGN PATENTS OR APPLICATlONS [22] Filed: Oct. 29, 1974 216,536 7/1958 Atistralia 273/106 A 1,103,364 2/1968 United Kingdom 273 106 A [21] Appl. No.2 518,886 a Related US. Application Data Primary Examiner- Paid E. Shapiro Attorney, Agent, or F irm-Baldwin, Wight & Brown 5 7] ABSTRACT The invention relates to a shuttlecock having a cap and a flared skirt of a plastics material and formed of a plurality of main stems interconnected by a lattice work of further stems and transverse ribs in which slits are provided in the wide end of the skirt extending to its free edge, between the main stems, the slits being adjacent the main stems. The main stems adjacent the base of the skirt may be provided with strengthening flanges extending approximately one-third of the length of the main stems.

14 Claims, 6 Drawing Figures SHUTTLECOCKS This application is a continuation-in-part of my copending application Ser. No. 458,012 filed Apr. 4, 1974, now abandoned.

This invention relates to shuttlecocks made of plastics material.

In order to obtain as true a flight as possible it is essential that a shuttlecock when in flight spins. Plastic shuttlecocks in order to be effective comprise a skirt which is attached to an independent base portion, made either from a synthetic material or ideally from cork. The skirt comprises a truncated conical lattice structure made up of main stems radiating from a diaphragm at the narrow end of the skirt and united to one another by ribs, the main stems in some cases being separated by subsidiary stems. For this purpose we have introduced into one of our designs main stems which are curved in the form of a helix, the helical stems standing proud of the surface of the skirt internally and/or externally and extending from the narrow to the wide end of the skirt. In an alternative construction, or in addition, as shown in U.K. Pat. Specification No. 926,049, there may be provided at the narrow end of the skirt rotation producing means consisting of a number of non-radial blades disposed internally of the skirt and commonly referred to as a rotor. The skirt is connected to the base portion by means ofa collar extending from the side of the diaphragm remote from the skirt, which collar is connected to the base.

According to the present invention, we provide a shuttlecock having a base and a frusto-conical skirt extending from said base, in which said skirt, which is formed of plastics material, comprises a truncated conical lattice structure made up of longitudinal main stems and subsidiary stems joined by transverse ribs, wherein said skirt is provided at its wide end with slits which extend from the wide end generally towards the base, said slits being at least three times as long in the longitudinal direction of the shuttlecock as they are wide, and having a width no greater than one-fifth the distance between main stems at the wide end of said skirt, there being only one slit between any adjacent pair of main stems.

The slits are preferably provided in that part of the lattice structure immediately adjoining the main stems. The slits may have parallel sides or tapering lines either vertical to the base or following the line of the main stems according to preference. In this respect, the main stems may be helically arranged, in which case, the slits would follow the line of the helix, and be on the opposite side of the helix to the side to which they extend, starting from the base.

The position and length of the slits in relation to the main stems determines the degree of spin. The standard feathered shuttlecock spins on its own axis in an anticlockwise direction, but special purpose shuttlecocks are also made which spin in a clockwise direction.

For the purpose of this invention as applied to a plastics shuttlecock with helical stems, looking at the shuttlecock with the narrow end of the skirt lowermost, the helix of the main stems runs from bottom left to top right and the slots are positioned in the top of the skirt to the left of the stems still looking at the shuttlecock as described above. If it is required to make a special shuttlecock to spin on its axis in a clockwise direction, the helix of the main stems would run from bottom right to top left and the slits would be to the right of the tops of the stems.

Another requirement is for the shuttlecock to fly accurately and for it to remain stable when struck and following reversal in direction of flight.

The success of any shuttlecock in good play isdetermined by the speed with which it recovers its true shape after being struck by a racquet. The degree of recovery is determined by the design of the bottom section of the sixteen main stems. To effect the quickest possible recovery the stems should be rigid, and it is a preferred feature of this invention that the stems have an at least substantially T or L or reverse L section from where they leave their anchorage to a diaphragm at the narrow end of the shuttlecock diaphragm to th e point where they blend in to the mesh section of the skirt. The tail of the T, L or inverted L is preferably greater in depth than the crossbar of the T at the diaphragm and the tails preferably taper in depth to nothing approximately one-third up the length of the main stems from the diaphragm. The crossbar of the T, L or inverted L may be semi-circular to triangularin cross section. The inside support flanges, i.e., the tail, may be parallel to the longitudinal axis of the shuttlecock, set at an angle to the axis or helically cut to coincide with the main stems if they are helical.

A stress relieving groove may be incorporated in the surface of the diaphragm facing the skirt to give maximum assistance to the shuttlecock to resist the blows of the racquet, and thus increase the playing life of the shuttlecock. Further flexibility may be provided by a 5/16 inch diameter hole in the centre of the diaphragm. It is believed that the stress relieving ring and the hole play a big part in giving long playing life to the shuttlecock.

The invention is illustrated by way of example in the accompanying drawings, in which:

FIG. 1 is a partly schematic elevation of a shuttlecock having a skirt formed with slits in accordance with one embodiment of the invention;

FIG. 2 is a view similar to that of FIG. 1 but showing a skirt having an alternative form of lattice structure provided with slits in accordance with the invention;

FIG. 3 is a section on the line IIIIII of FIG. 1;

FIG. 4a is an enlarged perspective view of part of a main stem in accordance with an alternative embodiment of the invention;

FIG. 4b is a section on the line VV of FIG. 4, and

FIG. 4c is a section similar to FIG. 4b, of a modified construction.

In FIG. 1 of the drawings, there is shown a shuttlecock comprising a skirt S and a base C, the skirt, which is formed of plastics material, having main stems l united by transverse ribs 3 forming the lattice structure. 2 indicates subsidiary stems which, in the embodiment illustrated, only extend part of the distance towards the narrow end of the skirt. There may be one subsidiary stem located centrally between each adjacent pair of main stems which is thicker than the other subsidiary stems (this is not illustrated).

In the shuttlecock of this invention, slits 4 are provided at the wide end of the skirt extending from the wide end downwardly towards the narrow end or base. The slits may, as shown, have parallel sides or sides which are convergent in the direction of the narrow end of the skirt material. Tests have shown that the provision of slits in accordance with this invention not only improves the stability of the shuttlecock in flight but assists in imparting spin. Best results are obtained when the slits 4 are immediately adjacent the main stems l on the convex side of the main stems when they are helically arranged (see FIG. I). This means that the periphery of the skirt, where it merges with a slit (as distinct from a main stem) tends to deform outwardly, tending to cause the shuttlecock to behave like a propeller in flight.

In FIG. 2, the shuttlecock, instead of having helical main stems, has straight ones, and in this case, the slits 4 are shown between the main stems I. It is preferred, however, that they are adjacent the main stems.

It will be understood that provision of slits in a shuttlecock skirt made of plastics material is not confined to the design of skirt shown in the drawings.

It could be applied, e.g., to the shuttlecock shown in UK. Pat. Specification Nos. 724,265, 763,756 and 926,049, or to most other designs of plastics shuttlecocks.

Referring to FIG. 3, it will be noted that at the narrow end of the skirt, the main stems terminate in a diaphragm 5 extending inwardly of the skirt. Approximately the bottom third of the skirt adjacent the diaphragm is comprised only of the main stems, the lattice stopping short of the diaphragm 5 to provide air passages 6 through which air can flow when the shuttlecock is in flight. In order to strengthen the main stems in the region of the air passages 6, the main stems are formed with an inwardly directed flange 7. For this purpose, each of the stems is substantially T-shaped, crosssection, the tail of the T, i.e., flange 7, being longer than the crossbar at the point where it merges with the diaphragm 5 and tapering gradually to no depth at the point on the stems 1 approximately where the lattice begins. As shown, the crossbar is substantially triangular, with the apex of the triangle pointing radially outwards. The flanges 7 are shown inclined in one direction across the crossbar, but it will be appreciated that they may be parallel to it, or inclined in the opposite direction.

In alternative stem constructions shown in FIGS. 4a, 4b and 4c, the main stem is of generally L or inverted L-shaped cross-section, the inwardly directed arm 12 of the L being longer than the crossbar arm 13 where the two join the base 5. Again, the arm 13 is generally triangular, but could be of different cross-section. It is important, however, that it is strong and at the same time not too heavy.

It will be noticed that the arm 12 makes an angle of about 70 with the face of the arm 13. This angle can vary. The arm 12 could also extend across the arm 13, instead of along one side, in one direction or the other, or could extend from the other side of the arm 13.

In the case of straight stemmed shuttlecocks, the tail or flange 7 is preferably located centrally of the stems and parallel to the stems so as to give a T-shaped crosssection. Alternatively, however, it may be on one side or the other of the stems so as to give an L- or inverted L-shaped cross-section. The flange may extend at right angles to the stem or at an angle somewhat less than a right angle and it may either be parallel to the stem or inclined relative thereto, for example from bottom left to top right. The relationship between one arm or flange and the other arm or cross piece will influence the degree of spin imparted to the shuttlecock. In the case of helical stems, the flanges may again be shaped as previously described to give a T, L or inverted L- shaped cross-section and they may extend across the helix so that, for example, in the case of a stem extending from bottom left to top right the flange would extend from bottom right to top left so as to assist with the spinning of the shuttlecock. Again, the flanges need not necessarily extend at right angles to the stem.

Where the flanges 7 join the diaphragm 5, a stress relieving groove 8 is formed in the diaphragm and preferably a central aperture 9 is formed in the diaphragm; the groove 8 and aperture 9 assist the shuttlecock in re sisting the blows of the racquet.

For a shuttlecock of standard size, i.e., a spread of 2%. inches diameter, the width of the slits may be from 1/64 inch to inch and their length may be up to inch. Preferably, however, they are about l/32 inch wide and inch long. Ideally, l6 slits are envisaged, one for each main stem. The skirt adjacent the tops of the slits could either be finished square (as shown in the drawings) or be rounded off with a radius of between /a inch to 3/16 inch. The sides and bottom of the slits are preferably sealed by slightly heavier lattice work 4a to prevent splitting in play, as shown in FIG. 1.

The dimensions given above are for a normal shuttlecock with a spread of 2 /2 inches diameter. It may be necessary to increase or decrease this spread to suit different playing conditions, i.e., at a high altitude, below average temperature or high humidity; in that case, the above dimensions may have to be increased or decreased in proportion.

In the drawings, open ended slits 2 are shown. It will be appreciated, however, that instead of providing slits, slots could be provided which would be closed off at the wide end of the skirt by a single transverse rib. The term slits in the appended claims is to be interpreted accordingly.

What is claimed is:

1. A shuttlecock having a base and a frusto-conical skirt extending from said base, in which said skirt, which is formed of plastics material, comprises a truncated conical lattice structure made up of longitudinal main stems and subsidiary stems joined by transverse ribs, wherein said skirt is provided at its wide end with slits which extend from the wide end generally towards the base, said slits being at least three times as long in the longitudinal direction of the shuttlecock as they are wide, and having a width no greater than l/5th the distance between main stems at the wide end of said skirt, there being only one slit between any adjacent pair of main stems.

2. A shuttlecock as claimed in claim 1 wherein the slits are provided in that part of said lattice structure immediately adjoining said main stems.

3. A shuttlecock as claimed in claim 1 wherein said main stems are helically arranged and said slits are provided adjacent the main stems on the opposite side of the main stems from that towards which the stems extend, starting from the narrow end of the skirt.

4. A shuttlecock as claimed in claim 3 wherein the slits are about 1/32 inch wide and about A inch long.

5. A shuttlecock as claimed in claim 1 wherein said main stems are straight.

6. A shuttlecock as claimed in claim 1 wherein a substantially radially directed strengthening flange is provided on each main stem over approximately a third of its length, starting from the narrow end of the shuttlecock.

7. A shuttlecock as claimed in claim 6 wherein said strengthened portions of said stems are of generally T- shaped cross-section.

8. A shuttlecock as claimed in claim 6 wherein said strengthened portions of said stems are of generally L- shaped cross-section.

9. A shuttlecock as claimed in claim 6 wherein said flange tapers from the base of the shuttlecock to nothing.

10. A shuttlecock as claimed in claim 6 wherein said flanges are parallel to the main stems.

11. A shuttlecock as claimed in claim 6 wherein the verted L-shaped cross-section. 

1. A shuttlecock having a base and a frusto-conical skirt extending from said base, in which said skirt, which is formed of plastics material, comprises a truncated conical lattice structure made up of longitudinal main stems and subsidiary stems joined by transverse ribs, wherein said skirt is provided at its wide end with slits which extend from the wide end generally towards the base, said slits being at least three times as long in the longitudinal direction of the shuttlecock as they are wide, and having a width no greater than 1/5th the distance between main stems at the wide end of said skirt, there being only one slit between any adjacent pair of main stems.
 2. A shuttlecock as claimed in claim 1 wherein the slits are provided in that part of said lattice structure immediately adjoining said main stems.
 3. A shuttlecock as claimed in claim 1 wherein said main stems are helically arranged and said slits are provided adjacent the main stems on the opposite side of the main stems from that towards which the stems extend, starting from the narrow end of the skirt.
 4. A shuttlecock as claimed in claim 3 wherein the slits are about 1/32 inch wide and about 1/4 inch long.
 5. A shuttlecock as claimed in claim 1 wherein said main stems are straight.
 6. A shuttlecock as claimed in claim 1 wherein a substantially radially directed strengthening flange is provided on each main stem over approximately a third of its length, starting from the narrow end of the shuttlecock.
 7. A shuttlecock as claimed in claim 6 wherein said strengthened portions of said stems are of generally T-shaped cross-section.
 8. A shuttlecock as claimed in claim 6 wherein said strengthened portions of said stems are of generally L-shaped cross-section.
 9. A shuttlecock as claimed in claim 6 wherein said flange tapers from the base of the shuttlecock to nothing.
 10. A shuttlecock as claimed in claim 6 wherein said flanges are parallel to the main stems.
 11. A shuttlecock as claimed in claim 6 wherein the flanges are inclined relative to the main stems.
 12. A shuttlecock as claimed in claim 6 wherein said skirt at its narrow end has a diaphragm closing it off and wherein an annular groove iS formed in said diaphragm, at the junction of said flanges with said diaphragm.
 13. A shuttlecock as claimed in claim 12 wherein an aperture is provided in the centre of said diaphragm.
 14. A shuttlecock as claimed in claim 6 wherein said strengthened portions of said stems are of generally inverted L-shaped cross-section. 